A reliable model system that is relevant to the disease in question is a critical asset to achieve development of safe and effective therapeutics. It is in particular relevant for glioblastoma, since this tumor is composed of heterogeneous multiple types of tumor cells in patients. Recent studies identified that application of the spheroid cultures enables us to maintain the original phenotypic and genetic characteristics of the parental tumors. Core C will utilize its current services to collect additional glioblastoma spheroids (GSs) from affected patients and uncover the phenotypic and genotypic characteristics of these GSs are particularly relevant to each project as detailed in aim 2. Specifically, we will establish spheroid cultures from surgical specimens and perform in vivo tumorigenicity assay to determine if our samples are able to recapitulate patients' tumors histopathologically. We also would plan to provide these services on an ongoing basis for all five years of the grant since characterized GSs transferred to each project may require re-characterization. As such, this Core will provide services essential to all 4 projects. Significance of this Core as a central biorepository will eliminate variability amongst the projects, ensuring that all projects utilize the same GSs for the proposed experiments.